Paroxysmal AF Originates from ectopic beats in the pulmonary veins in 94% of cases .
This likely relates to the anatomic transition from pulmonary vein endothelium to left atrial endocardium ; at this junction, two types of tissue with different electrical properties are juxtaposed and this may potentiate development of AF.
Although there is the critical importance of pulmonary vein in patients with paroxysmal AF, it may not apply to persistent or permanent AF.
As regards persistent & permanent AF Direct evidence is lacking , but clinical experience implicates the posterior left atrium & possibly the pulmonary veins in their pathogenesis and maintenance .
And in most patients, the left atrium acted as the electrical driving chamber
Isolation procedures do not actually terminate arrhythmias but rather confine them, their trigger mechanisms, or both to a desired region of the heart to minimize their adverse effects.
Ablation procedures preclude arrhythmias from developing either by destroying their trigger mechanism or by altering (or removing) the substrate that allows the arrhythmia to be induced and maintained.